Russian harassment and spying on U.S. diplomats in Moscow has increased significantly, an issue that U.S. Secretary of State John Kerry raised recently with Russian President Vladimir Putin.

Kerry last raised the matter with Putin in March, the State Department said on June 27.

"We see an increase and we take it seriously," department spokeswoman Elizabeth Trudeau said, adding that harassment by Russian security agents and traffic police had been an issue over the past two years since the U.S. imposed sanctions on Russia over its aggression in Ukraine.

Other Western embassies reported the same behavior toward their diplomats in Moscow, and the harassment of U.S. diplomats has occurred outside Russia as well, she said.

While Trudeau declined to name any specific official or incident, The Washington Post reported examples like intrusions into diplomats' homes in which their furniture was rearranged and lights and televisions were turned on. One diplomat said an intruder had defecated on his living room carpet.

Washington stripped five of Russia's six honorary consuls of credentials in January to retaliate for the harassment of its diplomats. In response, Russia's Foreign Ministry accused the United States of provoking Russian diplomats in the United States and elsewhere.

Honorary consuls are typically U.S. citizens who perform consular services on behalf of a foreign government. The five were located in California, Florida, Minnesota, Utah, and Puerto Rico.